The present invention relates to a fresh-air supply system for a ventilation device of a vehicle and, more particularly, to a fresh-air supply system in which the devices belonging to the ventilation system which must be protected from water can nevertheless be arranged simply in an accessible region of the fresh air duct after the vehicle hood is opened.
A fresh-air supply system is shown in German Patent 2,242,107 where the fresh-air duct initially extends obliquely downwards and rearwards as far as an overflow opening in an end wall of the bodywork, at which the bonnet-side duct portion ends. In order to permit a leakproof connection of the first duct portion to the second duct portion lying on the other side of the end wall when the bonnet is closed, a sealing profile made of an elastomeric material is arranged between a sealing flange of the second duct portion. The flange surrounds the overflow opening and a sealing flange of the first duct portion. The flange cooperates with the first flange.
The known fresh-air supply system is already distinguished by the fact that all units or the like lying underneath the swivelled-up duct portion after the opening of the bonnet are freely accessible. However, the fact that devices which require an installation position which is protected from water cannot be fitted without further measures in that region of the fresh-air duct which is accessible after the opening of the bonnet must be seen as disadvantageous. Such devices are, for example, a fan motor, a dust filter or an aggregation of these elements.
An object of the present invention is the provision of a fresh-air supply system for a vehicle ventilation device such that devices belonging to the ventilation system which require an installation position protected from water can be arranged without problems in that region of the fresh-air duct which is accessible after the opening of the bonnet.
This object has been achieved in accordance with the present invention by cooperating sealing flanges of two duct portions, lying in an approximately horizontal plane, and covered over by the engine hood. The first duct portion is a water-collecting box surrounding the air inlet opening and has a water drain. An overflow opening from the first duct portion to the second duct portion lies above the drainage level in the first duct portion to protect from direct ingress of water. It thereby is possible to prevent water from crossing from the first into the second duct portion with sufficient certainty. The arrangement of devices belonging to the ventilation system near to the sealing flange in the second duct portion in a manner protected from water is thus possible. The present invention thus makes it possible to guarantee easy access to the devices due to the fact that the sealing flange extends in an approximately horizontal plane.
In order to permit as flat a construction of the first duct portion as possible in combination with sufficient vertical overlap, the overflow opening can be arranged in the upper region of a connection piece which projects upward through the cross-section of passage of the upper sealing flange.
It is nevertheless advantageous if the sealing flange of the first duct portion likewise lies higher than the drainage level of this duct portion determined by the arrangement of the drainage device. As a result, the sealing flange is not subjected to the pressure of any temporary accumulation of water in the lowest region of the duct portion.
In order to be able to keep the cross-sectional extension of the first duct portion as small as possible, provision is made for the overflow opening to be partially overlapped by the air inlet opening. To ensure that no water can drip directly down into the overflow opening through the air inlet opening in this overlap region, a deflector profile configured as a collecting channel is provided. The channel is surrounded on three sides by raised walls and, on the fourth side, has a downward-angled overflow rim. In this embodiment, most of the water caught by the deflector profile can be guided off separately via a drainage connection of the deflector profile while the remainder runs off via the overflow rim into the lowest region of the first duct portion. Given a sufficient occurrence of water, the risk of accumulation in the first duct portion can be considerably increased thereby.
To prevent the accumulated water in the first duct portion from washing around the sealing flange of the latter, a baffle wall can be arranged in the sealing flange.
Due to the possibility of a compact configuration of the first duct portion due to a water-collecting box of narrow cross-section, the fresh-air supply system is especially suitable for a narrow and, at the same time, elongate air inlet opening.
So that a large-sized dust filter can be arranged in the cross-flow of the second duct portion despite the narrow cross-section of the first duct portion over the majority of its length, a widening of the first duct portion in an end region of the latter is provided, as a result of which the portion has an approximately L-shaped basic cross-section overall.
To make possible a low resistance deflection of the flow of the air as it passes into the connection piece, the overflow opening can be arranged transversely to the incident-flow direction of the air. Because the incident air is guided approximately horizontally below the deflector profile, the overflow opening must accordingly flow laterally into the connection piece. As a result, the overflow cross-section is considerably smaller than the cross-section of passage of the sealing flange. Accessibility of the second duct portion is maintained in the full cross-section of passage by providing the connection piece with a collar which cooperates like a cover with an opposite supporting flange and is connected in easily releasable fashion to the latter. The collar and the supporting flange thus together form the sealing flange of the second duct portion.